How do you find #(fog)(12)# given #f(x)=-4x+2# and #g(x)=sqrt(x-8)#?

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Answer 1 · 2017-03-29T08:56:38

The answer is #=-6#

This a composition of functions

#f(x)=-4x+2#

#g(x)=sqrt(x-8)#

#[fog] (x)=f(g(x))=f(sqrt(x-8))#

#=-4sqrt(x-8)+2#

Therefore,

#[fog] (12)=-4sqrt(12-8)+2#

#=-4*2+2#

#=-6#